1. Field of the Invention
The present invention relates to a color filter. The present invention also relates to a liquid crystal display device employing a color filter.
In particular, the present invention relates to a color filter which handles a first light ray and a second light ray. The first light ray has such a unidirectional optical path that the light ray incident from one principal plane side of the filter passes through the filter only once to be colored and is guided to the other principal plane side of the filter. The second light ray has such a bi-directional optical path that the light ray incident from the other principal plane side of the color filter passes through the filter to be colored and the passed light ray is reflected by an optical reflective element or the like disposed in the one principal plane side to enter the filter again and pass to be colored, and comes back to the other principle plane side. The invention also relates to a method of manufacturing the color filter. The invention further relates to a liquid crystal display device using such a color filter, and to a method of manufacturing the liquid crystal display device.
2. Description of Related Art
A liquid crystal display device, what is called the transflective type liquid crystal display device, becomes in full practical use, wherein external light incident from the front side is reflected to be guided to the front side while being provided with an optical modulation according to the image to be displayed, and incident light from the back light system on the rear side is passed to the same front side while being likewise provided with the optical modulation according to the image to be displayed. This type of liquid crystal display device effectively performs displays of image based on the external light (ambient light) mainly when the operating environment is bright (reflective mode) and based on emission light from the back light system mainly when it is dark (transmissive mode).
Such a type of liquid crystal display device is disclosed in a prior art document, “Development of Advanced TFT with Good Legibility under Any Intensity of Ambient Light” by M. Kubo et al., IDW' 99, Proceedings of The Sixth International Display Workshops, AMD3–4, page 183–186, Dec. 1, 1999, sponsored by ITE and SID. In this device, each pixel electrode is divided into a reflection area and a transmission area. The reflection area is a reflection electrode part formed from aluminium with which an acrylic resin with a rough surface is covered, and the transmission area is a transparent electrode part formed from ITO (Indium Tin Oxide) with a flat surface. The transmission area is situated in the center of a rectangular pixel area and has a substantially similar rectangular figure like the pixel area, whereas the reflection area is a part of the pixel area other than the rectangular transmission area and has a form of surrounding the transmission area. By virtue of the pixel configuration etc, the legibility is improved.